Develop of A Torque Feedback Interface for Virtual Acupuncture
Training
08118118, Shuang Peng, School of Automation
1. About
Haptic devices provide a straightforward method for mapping simulated forces to the user. This
enables the user to actively interact with the virtual environment. This makes them useful in
applications like medical training, where users can operate with virtual tissue before moving to real-
world patients. Acupuncture is a medical technique that inserts thin needles through patientβs skin
at bodyβs specific points. This report presents the development of a lightweight, highly backdrivable
torque feedback tip for virtual acupuncture training. The tip would be adapted to an existing
Phantom device.
2. Hardware
The acupuncture process mainly involves two motions, insertion of the needle and rotation in the
tissue. So the haptic device needs to render insert force and rotation torque in order to simulate the
acupuncture process on real-world patients. However, most existing commercial haptic devices are
equipped with 3 active translation DoF and 3 passive rotation DoF. Such as 3D systemsβ Phantom[1],
Falcon[2], and Omega[3]. For those with additional active rotation feedback hardware, motors and
transmission systems are directly mounted on the end-effector of the device. As a result, additional
weight and inertia can impact apparently on userβs experience. To address this issue, some solutions
compensated the tipβs weight on the software level with deviceβs dynamic model[4]. This project
proposed a tendon-based flex transmission structure that allows the tipβs actuation motor to be
decoupling mounted on deviceβs base. Which greatly decreases the tipβs moving weight. At the same
time, an origami-inspired clutch mechanism is designed to reduce the friction of free rotation. The
prototype of the tip is shown in Fig 1.
Fig 1 Prototype of the torque feedback tip
The design of the tip follows these guidelines.
Weight β Weight of the tip must be limited, without cause obvious changing on device's dynamic
property. Also, it should be easy and comfortable to operate by users.
Workspace β The added tip should not interfere deviceβs original workspace.